【摘要】 应用地块构造几何学方法和原理 ,系统研究了山西断陷带北部构造区地块构造类型、结构和运动特征 .运用断块“多米诺”模型 ,通过断裂构造地貌分析对比 ,系统地讨论了断块变形、断陷盆地伸展运动特点 ,及其区域分布特征 .分析结果显示 :①以北西向断裂划分 ,由西向东分为西区段、中区段和东区段 ,相应的地壳伸展量分别为 4 .4 6km ,2 .80km和1.86km .断块平均伸展量约为 1km .计算结果与实际测量数据大致相同 ;②以恒山断块为界 ,山西断陷带北部构造区可分为南北两区 ,两区地震活动水平不同 ,分别为M≥ 7和 6≤M<7,地震活动表现出明显差异性 .分析认为地震活动的差异性与地块运动方式及特点有关 .北部区断块向NW方向伸展 ,表现出张性地堑式扩展特征 .南部区地块掀斜运动特点 ,地块伸展运动方向向南东 ,与断裂倾向相反 .地块掀斜旋转在断裂上产生附加构造应力 ,这可能是南部区孕育大地震的主要因素之一 .更多还原

【Abstract】 This paper makes a systematical study on characteristics of structure and motion of the tectonic blocks in northern part of the Shanxi fault depression zone by means of geometrical and kinematical analysis of the blocks. The kinetic behavior of the blocks is discussed by comparing associated geomorphic features of fault movement. All analyses and studies are based on a Domino model. The block movement,fault basin extension and their regional distribution are systematically investigated. ① The study region is divided into subregions by NW striking faults: the western,middle and eastern subregion with crustal extension being 4.46 km,2.80 km and 1.86 km,respectively. The extensional amount of each block in the region is estimated being generally about 1 km. The calculated result using the block motion model approximately fits the data of geologic survey. ② Block kinematical features are obviously different between the northern and southern part,with the Hengshan block in between,of the study region. Moreover,the magnitude of the largest historical earthquake in the northern part is about 6,while that in the southern is 7. The faulted blocks in the northern subregion show northwestward extension,indicating a feature of extensional graben,while the blocks in the southern part manifest tilt motion,extending southeastward,in the opposite sense of fault dipping. Additional tectonic stress generated by block rotation may be one of major factors affecting seismogenic process in the region. It is responsible for the difference in the movement of the block boundary faults and seismic activities between the two subregions.更多还原